<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>表格边框合并</title>
  <style>
    table{
      border-collapse: collapse;
    }
  </style>
</head>

<body>
<table border='1'>
  <tr>
    <td>姓名</td>
    <td>性别</td>
    <td>年纪</td>
    <td>班级</td>
  </tr>
  <tr>
    <td>小明</td>
    <td>男</td>
    <td>18</td>
    <td>一年级</td>
  </tr>
  <tr>
    <td>小红</td>
    <td>女</td>
    <td>20</td>
    <td>一年级</td>
  </tr>
  <tr>
    <td>小明</td>
    <td>男</td>
    <td>18</td>
    <td>一年级</td>
  </tr>
  <tr>
    <td>小红</td>
    <td>女</td>
    <td>20</td>
    <td>一年级</td>
  </tr>
</table>

</body>

</html>
